Ruby: add convenience-accessors for ConstantValue

ruby/ql/lib/codeql/ruby/ast/Constant.qll

@@ -170,6 +170,24 @@ module ConstantValue {
 
   /** A constant `nil` value. */
   class ConstantNilValue extends ConstantValue, TNil { }
+
+  /** Gets the integer constant `x`. */
+  ConstantValue getInt(int x) { result.getInt() = x }
+
+  /** Gets the float constant `x`. */
+  ConstantValue getFloat(float x) { result.getFloat() = x }
+
+  /** Gets the string constant `x`. */
+  ConstantValue getString(string x) { result.getString() = x }
+
+  /** Gets the symbol constant `x`. */
+  ConstantValue getSymbol(string x) { result.getSymbol() = x }
+
+  /** Gets the regexp constant `x`. */
+  ConstantValue getRegExp(string x) { result.getRegExp() = x }
+
+  /** Gets the string, symbol, or regexp constant `x`. */
+  ConstantValue getStringlikeValue(string x) { result.getStringlikeValue() = x }
 }
 
 /** An access to a constant. */